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zephyr/drivers/serial/stellarisUartDrv.c

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/* stellarisUartDrv.c - Stellaris UART driver */
/*
* Copyright (c) 2013-2015 Wind River Systems, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* @brief Driver for Stellaris UART
*
* Driver for Stellaris UART found namely on TI LM3S6965 board. It is similar to
* an 16550 in functionality, but is not register-compatible.
*
* There is only support for poll-mode, so it can only be used with the printk
* and STDOUT_CONSOLE APIs.
*/
#include <nanokernel.h>
#include <arch/cpu.h>
#include <misc/__assert.h>
#include <board.h>
#include <uart.h>
#include <sections.h>
/* definitions */
/* Stellaris UART module */
struct _uart {
uint32_t dr;
union {
uint32_t _sr;
uint32_t _cr;
} u1;
uint8_t _res1[0x010];
uint32_t fr;
uint8_t _res2[0x04];
uint32_t ilpr;
uint32_t ibrd;
uint32_t fbrd;
uint32_t lcrh;
uint32_t ctl;
uint32_t ifls;
uint32_t im;
uint32_t ris;
uint32_t mis;
uint32_t icr;
uint8_t _res3[0xf8c];
uint32_t peripd_id4;
uint32_t peripd_id5;
uint32_t peripd_id6;
uint32_t peripd_id7;
uint32_t peripd_id0;
uint32_t peripd_id1;
uint32_t peripd_id2;
uint32_t peripd_id3;
uint32_t p_cell_id0;
uint32_t p_cell_id1;
uint32_t p_cell_id2;
uint32_t p_cell_id3;
};
/* convenience defines */
#define DEV_CFG(dev) \
((struct uart_device_config * const)(dev)->config->config_info)
#define UART_STRUCT(dev) \
((volatile struct _uart *)(DEV_CFG(dev))->base)
/* registers */
#define UARTDR(dev) (*((volatile uint32_t *)(DEV_CFG(dev)->base + 0x000)))
#define UARTSR(dev) (*((volatile uint32_t *)(DEV_CFG(dev)->base + 0x004)))
#define UARTCR(dev) (*((volatile uint32_t *)(DEV_CFG(dev)->base + 0x004)))
#define UARTFR(dev) (*((volatile uint32_t *)(DEV_CFG(dev)->base + 0x018)))
#define UARTILPR(dev) (*((volatile uint32_t *)(DEV_CFG(dev)->base + 0x020)))
#define UARTIBRD(dev) (*((volatile uint32_t *)(DEV_CFG(dev)->base + 0x024)))
#define UARTFBRD(dev) (*((volatile uint32_t *)(DEV_CFG(dev)->base + 0x028)))
#define UARTLCRH(dev) (*((volatile uint32_t *)(DEV_CFG(dev)->base + 0x02C)))
#define UARTCTL(dev) (*((volatile uint32_t *)(DEV_CFG(dev)->base + 0x030)))
#define UARTIFLS(dev) (*((volatile uint32_t *)(DEV_CFG(dev)->base + 0x034)))
#define UARTIM(dev) (*((volatile uint32_t *)(DEV_CFG(dev)->base + 0x038)))
#define UARTRIS(dev) (*((volatile uint32_t *)(DEV_CFG(dev)->base + 0x03C)))
#define UARTMIS(dev) (*((volatile uint32_t *)(DEV_CFG(dev)->base + 0x040)))
#define UARTICR(dev) (*((volatile uint32_t *)(DEV_CFG(dev)->base + 0x044)))
/* ID registers: UARTPID = UARTPeriphID, UARTPCID = UARTPCellId */
#define UARTPID4(dev) (*((volatile uint32_t *)(DEV_CFG(dev)->base + 0xFD0)))
#define UARTPID5(dev) (*((volatile uint32_t *)(DEV_CFG(dev)->base + 0xFD4)))
#define UARTPID6(dev) (*((volatile uint32_t *)(DEV_CFG(dev)->base + 0xFD8)))
#define UARTPID7(dev) (*((volatile uint32_t *)(DEV_CFG(dev)->base + 0xFDC)))
#define UARTPID0(dev) (*((volatile uint32_t *)(DEV_CFG(dev)->base + 0xFE0)))
#define UARTPID1(dev) (*((volatile uint32_t *)(DEV_CFG(dev)->base + 0xFE4)))
#define UARTPID2(dev) (*((volatile uint32_t *)(DEV_CFG(dev)->base + 0xFE8)))
#define UARTPID3(dev) (*((volatile uint32_t *)(DEV_CFG(dev)->base + 0xFEC)))
#define UARTPCID0(dev) (*((volatile uint32_t *)(DEV_CFG(dev)->base + 0xFF0)))
#define UARTPCID1(dev) (*((volatile uint32_t *)(DEV_CFG(dev)->base + 0xFF4)))
#define UARTPCID2(dev) (*((volatile uint32_t *)(DEV_CFG(dev)->base + 0xFF8)))
#define UARTPCID3(dev) (*((volatile uint32_t *)(DEV_CFG(dev)->base + 0xFFC)))
/* muxed UART registers */
#define sr u1._sr /* Read: receive status */
#define cr u1._cr /* Write: receive error clear */
/* bits */
#define UARTFR_BUSY 0x00000008
#define UARTFR_RXFE 0x00000010
#define UARTFR_TXFF 0x00000020
#define UARTFR_RXFF 0x00000040
#define UARTFR_TXFE 0x00000080
#define UARTLCRH_FEN 0x00000010
#define UARTLCRH_WLEN 0x00000060
#define UARTCTL_UARTEN 0x00000001
#define UARTCTL_LBE 0x00000800
#define UARTCTL_TXEN 0x00000100
#define UARTCTL_RXEN 0x00000200
#define UARTTIM_RXIM 0x00000010
#define UARTTIM_TXIM 0x00000020
#define UARTTIM_RTIM 0x00000040
#define UARTTIM_FEIM 0x00000080
#define UARTTIM_PEIM 0x00000100
#define UARTTIM_BEIM 0x00000200
#define UARTTIM_OEIM 0x00000400
#define UARTMIS_RXMIS 0x00000010
#define UARTMIS_TXMIS 0x00000020
static struct uart_driver_api stellaris_uart_driver_api;
/**
* @brief Set the baud rate
*
* This routine set the given baud rate for the UART.
*
* @param dev UART device struct (of type struct uart_device_config)
* @param baudrate Baud rate
* @param sys_clk_freq_hz System clock frequency in Hz
*
* @return N/A
*/
static void baudrate_set(struct device *dev,
uint32_t baudrate, uint32_t sys_clk_freq_hz)
{
volatile struct _uart *uart = UART_STRUCT(dev);
uint32_t brdi, brdf, div, rem;
/* upon reset, the system clock uses the intenal OSC @ 12MHz */
div = (16 * baudrate);
rem = sys_clk_freq_hz % div;
/*
* floating part of baud rate (LM3S6965 p.433), equivalent to
* [float part of (SYSCLK / div)] * 64 + 0.5
*/
brdf = ((((rem * 64) << 1) / div) + 1) >> 1;
/* integer part of baud rate (LM3S6965 p.433) */
brdi = sys_clk_freq_hz / div;
/*
* those registers are 32-bit, but the reserved bits should be
* preserved
*/
uart->ibrd = (uint16_t)(brdi & 0xffff); /* 16 bits */
uart->fbrd = (uint8_t)(brdf & 0x3f); /* 6 bits */
}
/**
* @brief Enable the UART
*
* This routine enables the given UART.
*
* @param dev UART device struct (of type struct uart_device_config)
*
* @return N/A
*/
static inline void enable(struct device *dev)
{
volatile struct _uart *uart = UART_STRUCT(dev);
uart->ctl |= UARTCTL_UARTEN;
}
/**
* @brief Disable the UART
*
* This routine disables the given UART.
*
* @param dev UART device struct (of type struct uart_device_config)
*
* @return N/A
*/
static inline void disable(struct device *dev)
{
volatile struct _uart *uart = UART_STRUCT(dev);
uart->ctl &= ~UARTCTL_UARTEN;
/* ensure transmissions are complete */
while (uart->fr & UARTFR_BUSY)
;
/* flush the FIFOs by disabling them */
uart->lcrh &= ~UARTLCRH_FEN;
}
/*
* no stick parity
* 8-bit frame
* FIFOs disabled
* one stop bit
* parity disabled
* send break off
*/
#define LINE_CONTROL_DEFAULTS UARTLCRH_WLEN
/**
* @brief Set the default UART line controls
*
* This routine sets the given UART's line controls to their default settings.
*
* @param dev UART device struct (of type struct uart_device_config)
*
* @return N/A
*/
static inline void line_control_defaults_set(struct device *dev)
{
volatile struct _uart *uart = UART_STRUCT(dev);
uart->lcrh = LINE_CONTROL_DEFAULTS;
}
/**
* @brief Initialize UART channel
*
* This routine is called to reset the chip in a quiescent state.
* It is assumed that this function is called only once per UART.
*
* @param dev UART device struct (of type struct uart_device_config)
*
* @return N/A
*/
void stellaris_uart_port_init(struct device *dev,
const struct uart_init_info * const init_info)
{
struct uart_device_config * const dev_cfg = DEV_CFG(dev);
dev_cfg->irq_pri = init_info->irq_pri;
disable(dev);
baudrate_set(dev, init_info->baud_rate, init_info->sys_clk_freq);
line_control_defaults_set(dev);
enable(dev);
dev->driver_api = &stellaris_uart_driver_api;
}
/**
* @brief Get the UART transmit ready status
*
* This routine returns the given UART's transmit ready status.
*
* @param dev UART device struct (of type struct uart_device_config)
*
* @return 0 if ready to transmit, 1 otherwise
*/
static int poll_tx_ready(struct device *dev)
{
volatile struct _uart *uart = UART_STRUCT(dev);
return (uart->fr & UARTFR_TXFE);
}
/**
* @brief Poll the device for input.
*
* @param dev UART device struct (of type struct uart_device_config)
* @param c Pointer to character
*
* @return 0 if a character arrived, -1 if the input buffer if empty.
*/
static int stellaris_uart_poll_in(struct device *dev, unsigned char *c)
{
volatile struct _uart *uart = UART_STRUCT(dev);
if (uart->fr & UARTFR_RXFE)
return (-1);
/* got a character */
*c = (unsigned char)uart->dr;
return 0;
}
/**
* @brief Output a character in polled mode.
*
* Checks if the transmitter is empty. If empty, a character is written to
* the data register.
*
* @param dev UART device struct (of type struct uart_device_config)
* @param c Character to send
*
* @return Sent character
*/
static unsigned char stellaris_uart_poll_out(struct device *dev,
unsigned char c)
{
volatile struct _uart *uart = UART_STRUCT(dev);
while (!poll_tx_ready(dev))
;
/* send a character */
uart->dr = (uint32_t)c;
return c;
}
#if CONFIG_UART_INTERRUPT_DRIVEN
/**
* @brief Fill FIFO with data
*
* @param dev UART device struct (of type struct uart_device_config)
* @param tx_data Data to transmit
* @param len Number of bytes to send
*
* @return Number of bytes sent
*/
static int stellaris_uart_fifo_fill(struct device *dev, const uint8_t *tx_data,
int len)
{
volatile struct _uart *uart = UART_STRUCT(dev);
uint8_t num_tx = 0;
while ((len - num_tx > 0) && ((uart->fr & UARTFR_TXFF) == 0)) {
uart->dr = (uint32_t)tx_data[num_tx++];
}
return (int)num_tx;
}
/**
* @brief Read data from FIFO
*
* @param dev UART device struct (of type struct uart_device_config)
* @param rx_data Pointer to data container
* @param size Container size
*
* @return Number of bytes read
*/
static int stellaris_uart_fifo_read(struct device *dev, uint8_t *rx_data,
const int size)
{
volatile struct _uart *uart = UART_STRUCT(dev);
uint8_t num_rx = 0;
while ((size - num_rx > 0) && ((uart->fr & UARTFR_RXFE) == 0)) {
rx_data[num_rx++] = (uint8_t)uart->dr;
}
return num_rx;
}
/**
* @brief Enable TX interrupt
*
* @param dev UART device struct (of type struct uart_device_config)
*
* @return N/A
*/
static void stellaris_uart_irq_tx_enable(struct device *dev)
{
static uint8_t first_time =
1; /* used to allow the first transmission */
uint32_t saved_ctl; /* saved UARTCTL (control) register */
uint32_t saved_ibrd; /* saved UARTIBRD (integer baud rate) register */
uint32_t saved_fbrd; /* saved UARTFBRD (fractional baud rate) register
*/
volatile struct _uart *uart = UART_STRUCT(dev);
if (first_time) {
/*
* The Tx interrupt will not be set when transmission is first
* enabled.
* A character has to be transmitted before Tx interrupts will
* work,
* so send one via loopback mode.
*/
first_time = 0;
/* save current control and baud rate settings */
saved_ctl = uart->ctl;
saved_ibrd = uart->ibrd;
saved_fbrd = uart->fbrd;
/* send a character with default settings via loopback */
disable(dev);
uart->fbrd = 0;
uart->ibrd = 1;
uart->lcrh = 0;
uart->ctl = (UARTCTL_UARTEN | UARTCTL_TXEN | UARTCTL_LBE);
uart->dr = 0;
while (uart->fr & UARTFR_BUSY)
;
/* restore control and baud rate settings */
disable(dev);
uart->ibrd = saved_ibrd;
uart->fbrd = saved_fbrd;
line_control_defaults_set(dev);
uart->ctl = saved_ctl;
}
uart->im |= UARTTIM_TXIM;
}
/**
* @brief Disable TX interrupt in IER
*
* @param dev UART device struct (of type struct uart_device_config)
*
* @return N/A
*/
static void stellaris_uart_irq_tx_disable(struct device *dev)
{
volatile struct _uart *uart = UART_STRUCT(dev);
uart->im &= ~UARTTIM_TXIM;
}
/**
* @brief Check if Tx IRQ has been raised
*
* @param dev UART device struct (of type struct uart_device_config)
*
* @return 1 if a Tx IRQ is pending, 0 otherwise
*/
static int stellaris_uart_irq_tx_ready(struct device *dev)
{
volatile struct _uart *uart = UART_STRUCT(dev);
return ((uart->mis & UARTMIS_TXMIS) == UARTMIS_TXMIS);
}
/**
* @brief Enable RX interrupt in IER
*
* @param dev UART device struct (of type struct uart_device_config)
*
* @return N/A
*/
static void stellaris_uart_irq_rx_enable(struct device *dev)
{
volatile struct _uart *uart = UART_STRUCT(dev);
uart->im |= UARTTIM_RXIM;
}
/**
* @brief Disable RX interrupt in IER
*
* @param dev UART device struct (of type struct uart_device_config)
*
* @return N/A
*/
static void stellaris_uart_irq_rx_disable(struct device *dev)
{
volatile struct _uart *uart = UART_STRUCT(dev);
uart->im &= ~UARTTIM_RXIM;
}
/**
* @brief Check if Rx IRQ has been raised
*
* @param dev UART device struct (of type struct uart_device_config)
*
* @return 1 if an IRQ is ready, 0 otherwise
*/
static int stellaris_uart_irq_rx_ready(struct device *dev)
{
volatile struct _uart *uart = UART_STRUCT(dev);
return ((uart->mis & UARTMIS_RXMIS) == UARTMIS_RXMIS);
}
/**
* @brief Enable error interrupts
*
* @param dev UART device struct (of type struct uart_device_config)
*
* @return N/A
*/
static void stellaris_uart_irq_err_enable(struct device *dev)
{
volatile struct _uart *uart = UART_STRUCT(dev);
uart->im |= (UARTTIM_RTIM | UARTTIM_FEIM | UARTTIM_PEIM |
UARTTIM_BEIM | UARTTIM_OEIM);
}
/**
* @brief Disable error interrupts
*
* @param dev UART device struct (of type struct uart_device_config)
*
* @return N/A
*/
static void stellaris_uart_irq_err_disable(struct device *dev)
{
volatile struct _uart *uart = UART_STRUCT(dev);
uart->im &= ~(UARTTIM_RTIM | UARTTIM_FEIM | UARTTIM_PEIM |
UARTTIM_BEIM | UARTTIM_OEIM);
}
/**
* @brief Check if Tx or Rx IRQ is pending
*
* @param dev UART device struct (of type struct uart_device_config)
*
* @return 1 if a Tx or Rx IRQ is pending, 0 otherwise
*/
static int stellaris_uart_irq_is_pending(struct device *dev)
{
volatile struct _uart *uart = UART_STRUCT(dev);
/* Look only at Tx and Rx data interrupt flags */
return ((uart->mis & (UARTMIS_RXMIS | UARTMIS_TXMIS)) ? 1 : 0);
}
/**
* @brief Update IRQ status
*
* @param dev UART device struct (of type struct uart_device_config)
*
* @return Always 1
*/
static int stellaris_uart_irq_update(struct device *dev)
{
return 1;
}
/**
* @brief Returns UART interrupt number
*
* Returns the IRQ number used by the specified UART port
*
* @param dev UART device struct (of type struct uart_device_config)
*
* @return N/A
*/
static unsigned int stellaris_uart_irq_get(struct device *dev)
{
return (unsigned int)DEV_CFG(dev)->irq;
}
#endif /* CONFIG_UART_INTERRUPT_DRIVEN */
static struct uart_driver_api stellaris_uart_driver_api = {
.poll_in = stellaris_uart_poll_in,
.poll_out = stellaris_uart_poll_out,
#ifdef CONFIG_UART_INTERRUPT_DRIVEN
.fifo_fill = stellaris_uart_fifo_fill,
.fifo_read = stellaris_uart_fifo_read,
.irq_tx_enable = stellaris_uart_irq_tx_enable,
.irq_tx_disable = stellaris_uart_irq_tx_disable,
.irq_tx_ready = stellaris_uart_irq_tx_ready,
.irq_rx_enable = stellaris_uart_irq_rx_enable,
.irq_rx_disable = stellaris_uart_irq_rx_disable,
.irq_rx_ready = stellaris_uart_irq_rx_ready,
.irq_err_enable = stellaris_uart_irq_err_enable,
.irq_err_disable = stellaris_uart_irq_err_disable,
.irq_is_pending = stellaris_uart_irq_is_pending,
.irq_update = stellaris_uart_irq_update,
.irq_get = stellaris_uart_irq_get,
#endif
};
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